The most popular boat which can be run by human power is the boat in which an oar is pulled by occupant's hands. The boat with such a human-powered propelling oar has some propulsion efficiency but both hands have to be occupied pulling the oar, and the occupant's body weight is not used for propelling the boat. Therefore, the boat with the propelling oar is limited in the occupant's operation position and movement and the efficiency is not good enough.
Various different forms of human-powered boat propulsion equipments without the propelling oar heretofore have been provided. Almost all the foot-operated boat propelling equipments are pedal cycling drives, such as those disclosed in U.S. Pat. Nos. 650,224, 1,462,027, 1,471,747, 2,664,064, 2,703,065, 3,211,125, 4,891,024, and 4,960,396. However, all the propelling devices have the problems in that the construction thereof is complicated and voluminous, and that they could not make good use of occupant's body weight for propelling the boat. U.S. Pat. No. 4,936,802 shows a "Swing and Propelling ship", by using a wing-like fin. However, the propulsive efficiency is poor and the operator become easily tired.